Dietary isoflavones, the modulator of breast carcinogenesis: Current landscape and future perspectives

Breast cancer is a frightful disease and serious concern in women around the world causing significant health care burden in both developed and developing countries. Extensive research work has shown that breast cancer provides strong resistance to chemical agents, UV radiation, and hormonal treatments. It is generally accepted that cell genetics is not the only main reason for breast cancer and genetic risk factors, for example, mutations in BRCA1 and BRCA2 genes constitute 5%-10% of all breast cancer rates. Other related factors include age, gender, race, ethnicity, weight, reproductive factors, exo- and endogenous hormonal exposures, oral contraceptives use, ultraviolet radiation, diet, and night work (circadian disruption). Many studies have revealed that dietary isoflavones regulate breast cancer occurrence, recurrence and prognosis. Dietary isoflavones have long been part of Asian population diet and there is a significant increase as compared to dietary isoflavones intake among other populations. Dietary isoflavones are natural phytoestrogens having both estrogenic and anti-estrogenic potentials on breast cancer cells in culture, animal models and in experimental trials. This literature survey provides a comprehensive overview on the tumor preventive and tumor promoting potentials of dietary isoflavones on breast cancer. In addition, this paper provides a literature review of dietary isoflavones and their effects on up-regulation and down-regulation of different signaling pathways, genes and proteins. Finally, future perspectives of dietary isoflavones and breast cancer researchers are also critically discussed, which will provide a deeper insight regarding the inner molecular mechanisms of action